093 
FXUS63 KBIS 021148
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
648 AM CDT Fri Aug 2 2019

.UPDATE...
Issued at 646 AM CDT Fri Aug 2 2019

Patchy dense fog has developed across portions of southwest and
south central North Dakota. The fog should dissipate by around 9 
AM MDT. Elsewhere, the thunderstorms that were over the James 
River Valley during the night have moved off to the east, while 
scattered showers continue over north central North Dakota. Models
continue to struggle with the north central activity, as well as 
the low stratus deck over south central North Dakota. Updates to 
PoPs and sky were based on observational trends.

&&

.SHORT TERM...(Today and tonight)
Issued at 414 AM CDT Fri Aug 2 2019

A mid level low spinning over North Dakota is responsible for 
scattered showers and thunderstorms early this morning. The heaviest 
activity over the past couple hours has been centered over the James 
River Valley. Radar estimates indicate that 2 to 3 inches of rain 
have fallen over parts of eastern Dickey County over the past couple 
hours. Other scattered shower activity extends across north central 
North Dakota, which is not being captured by models. Also monitoring 
for potential fog development early this morning. Light winds, low 
dewpoint depressions, and recent rainfall for many areas, but there 
may be just enough cloud cover to prevent widespread fog from 
developing.

The mid level low will meander into eastern South Dakota today, 
continuing chances for showers and thunderstorms. Despite the 
presence of around 2000 J/kg CAPE this afternoon, mid level lapse 
rates less than 6 C/km and deep layer shear less than 20 kts should 
preclude any severe threat. It may be worthing noting that several 
parameters are favorable for non-supercell funnel clouds/landspouts.
However, the lack of a marked surface wind shift should mitigate 
this threat, although there could be numerous outflow boundaries 
present. Chances for showers and storms will diminish in the 
evening as the mid level low drifts farther away from the region.

.LONG TERM...(Saturday through Thursday)
Issued at 414 AM CDT Fri Aug 2 2019

The general synoptic pattern through the extended period calls for 
upper level ridging over the Rockies and longwave troughing over 
eastern North America. Several waves rounding the top of the ridge 
will bring shower and thunderstorm chances to the area at various 
times. Temperatures are expected to be near normal.

The first chance for showers and storms will be Saturday. A mid 
level shortwave is forecast to move into North Dakota by the 
afternoon, and some models show convection out ahead of this 
feature. Farther to the west, a surface trough is forecast to lie in 
the vicinity of the North Dakota/Montana border by late afternoon. 
There are questions on whether there will be enough forcing for 
convective initiation along the surface boundary, but strong diurnal 
heating and subtle mid level height falls should weaken CIN. At this 
time, think storms would be isolated if they form. Instability and 
shear parameters would support a low end severe threat.

On Sunday, a strong low pressure system is forecast to approach 
Hudson Bay, with a trailing cold front extending back all the way 
into North Dakota. This front will be the focus for another chance 
of showers and storms Sunday afternoon through Sunday night. 
Instability and shear will be stronger than Saturday, sufficient for 
storms to become severe. There may also be a heavy rain threat 
Sunday as storm motion vectors are forecast to be oriented nearly 
parallel to the boundary.

Beyond the weekend, it looks a bit quieter for a few days, with 
active weather possible again by the end of the week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 646 AM CDT Fri Aug 2 2019

Patchy dense fog will impact KDIK until around 14Z this morning.
At KBIS, expect IFR ceilings until around 14Z. Think that the
cloud deck will start to scatter out at that time, but an
extension to IFR conditions may be needed. Aside from the fog/low
stratus across southwest and south central ND this morning, VFR
conditions are expected, though fog could redevelop towards the 
end of this TAF cycle. Scattered showers near KMOT this morning 
are not expected to cause significant aviation impacts. This
afternoon, scattered showers and thunderstorms are forecast to 
redevelop over southeast ND, and may approach KJMS. Winds will 
remain south-southeasterly and light through the forecast period.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Hollan
SHORT TERM...Hollan
LONG TERM...Hollan
AVIATION...Hollan